Normal hair can be so fine and limp, and so lacking in body that the hair does not hold a hair set well. Furthermore, the hair can become even less bodied and can be weakened further as a result of being subjected to chemically active hair treatments, such as permanent waves and tints. Additionally, hair can be weakened even further by other contributing factors, such as bleaching by sun exposure and/or chlorinated swimming pool water.
Normal hair is usually hydrophobic. However, many of the chemically active hair treatments remove the natural hydrophobic components from the hair. As a result, as the hydrophobicity of the hair decreases, the relative porosity of the hair increases and the hair tends to absorb water and swell more readily. In such a weakened and porous state, the water-swollen hair is more vulnerable to stretching and breaking.
Since hair setting is basically the process of shaping wet hair by the steps of stretching the hair by curling the hair, fixing the hair in place by drying, then combing to give the finishing touches to provide the desired hairstyle, the overall condition of the hair is an important factor in achieving an acceptable hair set. In particular, the setting of wet hair can be accomplished by making flat curls from strands of hair and fixing the curls with hairpins to produce "pin curls". Similarly, the wet hair can be set by using any of a variety of rollers or curlers to mechanically fix the hair. In either case, the winding of the wet hair is followed by drying, either by ambient air drying, electric drying or hot air drying.
The inherent problem encountered in hair setting is the natural tendency of the hair to return to its natural shape. For example, the set hair returns to its natural shape almost immediately if moistened. Likewise, high humidity conditions accelerate the tendency of the hair to return to its natural shape. Therefore, intensive efforts have been directed toward providing a hair set with sufficient holding power to maintain the designed hair style until at least the next shampoo, and therefore giving the hair set a degree of permanency.
As shown by the natural tendency of hair to return to its natural shape, hair is an elastic structure. As a result, the slight deformations in the hair structure resulting from setting the hair are completely reversible. However, the rate of return of the hair to its natural shape is dependent upon the method used to deform, or set, the hair. Hair sets performed with wet strands of hair being rolled tightly, either in curls around the finger or on curlers, followed by drying the hair and unrolling the curlers after drying, corresponds to the release of the hair from a deformation-causing load. The deformation, or set, obtained can last for several days, but the set will not be retained if the hair is wetted.
The observations of hair deformation and relaxation are related to physical and chemical changes in the protein structure level of hair. Sufficient stretching of the hair causes partial transformation of the .alpha.-keratin protein structure of the hair into the .beta.-keratin protein structure of the hair. This structural transformation is accompanied by a shift in relative position of the polypeptide chains that is facilitated by water moistening the hair. The shift in position of the polypeptide chains therefore disrupts the ionic and hydrogen bonds in the hair. During the drying procedure, new ionic and hydrogen bonds are formed that block the return to the .alpha.-keratin protein structure of hair. Gradually, the new protein linkages give way under natural forces, such that the hair returns to its original state and length. If the hair is moistened, the return to the .alpha.-keratin form is virtually immediate.
Therefore, investigators have sought to delay the combined action of natural forces and moisture that cause the hair to return to its original state by utilizing solutions containing naturally-occurring or synthetic polymers. When applied to the hair from aqueous or aqueous/alcoholic solutions, the polymers leave a film on the hair after drying. The polymeric film promotes cohesion and gives stability to the hair set, and therefore setting lotions containing polymers have been devised to maintain the hold of the hair set. The principal objective of the setting lotion is to cover the styled hair with an invisible polymeric film that will give the styled hair a degree of rigidity and protect the hair style against wind and humidity.
Hair spray products act in a similar manner. The hair spray products are applied to wet and/or dry hair and generally are not rinsed out. Like hair setting lotions, the hair spray contains polymers, or mixtures of polymers, that remain fixed on the hair and affect the hair in various ways. For example, a "mechanical" effect is exerted on each individual hair. The film-forming polymers are used to provide a flexible sheath of polymeric film on the hair after drying, and therefore, for mechanical reasons, retard the return of each individual hair to its natural shape. In addition, the polymeric film provides an overall stiffening of the hair. The hair behaves as if the individual hair strands are welded together, and the final hairstyle has better cohesion, therefore resisting the natural forces that return the hair to its natural shape. Finally, the polymeric film protects the hair from humidity. The ability of the polymeric film to attract and absorb water is preferably minimal, such that the polymeric film retards moisture uptake by hair and retards the return of the hair to the .alpha.-keratin hair protein structure.
The general principles of hair setting are thoroughly discussed by C. Zviak, in The Science of Hair Care, Marcel Dekker, pp. 149-181 (1986). Zviak reviews both the polymers used in hair setting products and the formulation principles used to produce a hair set product that provides such beneficial hair set properties as improved hair style hold, easy application and combing, quick drying and non-stickiness, good hair body and bounce, increased hair volume and gloss, and hydrophobicity. It is evident that in the formulation of any end-use product, some of these benefits must be sacrificed to some degree to achieve a competing benefit. Therefore, the formulation of hair set products has proved difficult, and, as a result, hair set products have been developed in a variety of product forms.
The prior art reveals that nonionic, cationic and anionic polymers have been used in hair set products, with the anionic polymers providing the best hair set results. However, anionic polymers also have disadvantages, such as high water solubility, therefore low hydrophobicity, and low substantivity to hair fibers, therefore easy elimination from the hair by combing and brushing. As a result, investigators have continued to search for compounds and compositions that provide the benefits of an anionic surfactant-based hair set product plus an improved durability of the hair set. As previously mentioned, to overcome some of the inherent disadvantages of the polymers utilized to set the hair, hair set products are made available in diversified forms in an attempt to minimize the drawbacks of the particular polymer used in the formulation. For example, hair set products are available as plasticizing lotions, plasticizing gels, aerosol foams, all-purpose lotions, hair sprays, holding lotions, conditioners and shampoos.
Although commercially available products relying upon polymeric materials produce bodying effects on the hair, these products usually do not provide improvements in hair hydrophobicity against the known adverse effects of humidity in maintaining a hair style. In some cases, the hair treating products make the hair hard to comb or can absorb moisture themselves. One other effort to make hair hydrophobic is to apply oily hair dressings and creams to the hair, wherein the oily product is left on the hair to act as a physical barrier against moisture uptake. However, these oily products provide only a temporary barrier that is removed when the consumer washes her or his hair. In addition, these oily products frequently impart the hair with a dull and heavy coating, thereby sacrificing the bodying benefits desired by persons having fine, limp, porous hair. Consequently, in using presently available commercial products, consumers must sacrifice certain desirable physical characteristics of the hair in order to achieve or improve other desirable physical characteristics.
The present invention relates to a composition and method of treating the hair to improve the physical properties of the treated hair. It has been found that by treating the hair with compositions including a water-insoluble amino-containing compound and an ionizable metal salt, wherein the metal has a valence of at least II, the physical properties of the hair are improved such that the hair will retain the shape of the hair set and will not revert to its natural shape upon contact with moisture, and, more surprisingly, will retain the shape of the hair set even after a subsequent shampooing. Thus, the imprOVed hair set retention properties imparted to the hair upon treatment with the composition of the present invention obviates the need to treat the hair each day or after each shampooing.
Various effects resulting from treating human hair with metal salts and/or amines are known. For example, polyvalent metal salts are known in the art for their astringent and antiperspirant effects on skin. Hewitt et al, in U.S. Pat. No. 3,842,847, taught the use of astringent water-soluble salts of aluminum, hafnium, zirconium, zinc and like metals in a shampoo and hair treatment to diminish scalp perspiration. Hewitt et al also reported antistatic and anti-soiling effects on hair treated with aqueous rinses including aluminum chlorohydrate. Hewitt et al theorized that the astringent metal salt reacted with the hair keratin to reduce the anionic nature of the hair, and therefore, to reduce "fly-away" hair. However, to obtain the benefits disclosed by Hewitt et al, the hair had to be water rinsed after treatment until the pH of the rinse water was at least over 6. In contrast, to achieve the benefits of the present invention, the hair treating composition does not have to be rinsed from the hair.
Cassidy, in U.S. Pat. No. 3,208,910, disclosed the use of a water-soluble zirconium carboxylate salt in a hair styling fluid to impart body, moisture resistance and sheen to human hair. Zirconium acetate, present in a concentration of 0.1 percent to 2 percent in a composition having a pH from about 3 to about 6, was used in a treatment for setting the hair. However, the treated hair behaved as if it were full of snarls and the hair was extremely difficult to comb when the concentration of zirconium acetate exceeded 2 percent. Consequently, body-enhancing and moisture-resistant effects could be imparted only by including auxiliary dispersing agents, waxes and polymers; or by washing the hair with a soap shampoo to form an insoluble zirconium soap on the hair. However, in accordance with the present invention, the absolute concentration of the water-soluble metal salt is not limited and auxiliary agents, except for the water-insoluble amino-containing compound, are not required to produce the new and unexpected results of the present invention.
Similarly, Anzuino and Robbins, in the publication "Reactions of Metal Salts with Human Hair Containing Synthetic Polymers", J. Soc. Cosmet. Chem., 22, 179-186 (1971), taught the polymerization of vinyl monomers, such as methacrylic acid or N,N-dimethylaminoethyl methacrylate, within the keratin fibers of the hair to alter the chemical reactivity of the keratin. Then the polymer-containing hair fibers were reacted with metal salts, such as calcium chloride, nickel chloride, or zinc acetate, to improve the wet load extension properties of the hair. However, the method disclosed by Anzuino and Robbins involves a chemical reduction of the hair that imparts roughness, color lightening and other undesirable properties to the hair. In contrast, the composition and method of the present invention does not involve a chemical reduction of the hair protein, and therefore is not damaging to the hair fiber.
Homan, in U.S. Pat. No. 4,487,883, disclosed the use of a polymer having at least one nitrogen-hydrogen bond and an anhydrous additive, like a titanate, zirconate, or vanadate, in a hair-treating composition. According to the teachings of Homan, after application to the hair, the polymer is crosslinked upon exposure to moisture or humidity to provide hair conditioning and a hair set. A subsequent shampooing breaks the crosslinking bond, and the polymer, now in its original form, still acts as a conditioner, but does not act as a hair set. Therefore, the hair setting properties provided by the compositions disclosed by Homan are lost as soon as the treated hair is wetted. The compositions disclosed by Homan further suffer from the disadvantage of having to be stored in an anhydrous state. Such storage conditions usually are not practically feasible because it is difficult to insure that a commercial product remains moisturefree under normal production and storage conditions. Conversely, the composition of the present invention is not limited to polymeric nitrogen-containing compounds, and the present composition has an aqueous base thereby allowing normal production conditions and a variety of formulation choices. Furthermore, a subsequent shampooing of hair treated with the composition of the present invention will not destroy the hair set properties imparted by the hair treatment.
European patent application No. 0117360 teaches the use of an aqueous composition including an emulsified polymer having at least one nitrogenhydrogen bond and an organic zirconate, germanate and/or titanate, and having a pH of 6 to 8, in a process to condition and set the hair. The method and composition disclosed in European patent application 0117360 differs from the present invention in that the European disclosure operates well outside the pH range of the present invention and, more importantly, the composition applied to the hair, as taught in the European application, does not maintain the hair set properties of the hair after a shampooing. In contrast to the present invention, wherein the hair set retention properties are retained through more than one shampooing, the composition of the European disclosure reverts to a non-crosslinked polymer after a single shampooing to act only as a hair conditioner.
In U.S. Pat. No. 4,283,384, Jacquet et al disclosed a composition including a particular type of polymer produced from an unsaturated monomer such as acrylic acid, a compound containing at least one hydroxyl functionality such as polyvinyl alcohol or pentaerythritol, and cerium ion. The polymer imparts good holding power to hair when the polymer is applied to the hair in a shampoo formulation. In the method of Jacquet, the cerium ion apparently is not involved in the interaction between hair and polymer. Initially, the effects of the Jacquet et al composition on the hair match the effects provided by the present invention. However, Jacquet et al do not disclose or suggest that their composition imparts an especially durable hair set to the hair. In contrast, the present invention exhibits unexpected durability by maintaining the desired hair set properties through at least one shampooing after treatment.
Jachowicz et al, in U.S. Pat. No. 4,588,760, disclosed applying an aqueous solution containing a heximinium salt and resorcinol to the hair such that an in situ polymerization reaction occurs to improve hair set retention properties. However, to provide the benefits of improved hair set retention, the composition of Jachowicz et al must contact the hair for a period of time ranging from 0.25 hours to 16 hours. Surprisingly, the method and composition of the present invention unexpectedly impart excellent hair set retention characteristics to the hair within 2 minutes, generally the time required to comb the composition through the hair. U.S. Pat. No. 4,588,760 taught that the quaternary ammonium halide salts of hexamethylene tetramine undergo complexing and polymerization with resorcinol within the hair fibers to form a condensation polymer. Overall, the method of Jachowicz is time-consuming and complicated, and uses potentially toxic materials, especially in comparison to the composition and the method of the present invention.
In U.S. Pat. No. 4,614,200, Hsiung et al disclosed utilizing an aqueous aluminum salt solution, without an amino-containing compound, to improve the set retention properties of hair at an ambient relative humidity of 50-60%. However, unlike the composition of the present invention, at higher relative humidities of approximately 80%, aluminum chloride solutions without amino-containing compounds exhibit poor set retention properties. Furthermore, the method of Hsiung et al specifically excludes using certain metal salts, such as zinc salts, that have provided excellent hair set retention results in accordance with the present invention. For example, a composition including zinc chloride and an amino-functionalized silicone provided excellent hair set retention properties in accordance with the composition and method of the present invention.
Accordingly, to date, the compositions and methods used to set hair have suffered from poor set retention times, from sacrificing one beneficial hair property in order to achieve another beneficial hair property, and/or from abnormally long times to treat the hair. Prior to the present invention, no known method or composition has been employed to effectively treat hair within a few minutes to provide a durable hair set that is preserved through at least one shampooing subsequent to the hair setting treatment.
Therefore, in accordance with the present invention, hair setting treatments are surprisingly and unexpectedly improved by contacting the hair with a composition including a water-insoluble amino-containing compound and an ionizable metal salt, wherein the metal has a valence of at least II. The water-insoluble amino-containing compound and the ionizable metal salt can be applied to the hair from an aqueous or aqueous/alcoholic vehicle at ambient temperature and is allowed to contact the hair for relatively short times to provide the benefits and advantages of the present invention. Therefore, as will be demonstrated more fully hereinafter, the method and composition of the present invention provides an aesthetically pleasing hair set that does not damage the hair and is durable through at least three subsequent shampooings.